Crohn's disease (CD) and ulcerative colitis (UC) are chronic remitting and relapsing inflammatory disorders of the gastrointestinal tract that are collectively called the inflammatory bowel diseases (IBD). While increasingly effective therapies have come into use, these diseases continue to result in significant short and long term morbidity, surgery, and disability. IBD is believed to result from dysregulation of the gut's immune system occurring in genetically predisposed individuals who are exposed to one or more unknown environmental triggers. Trends of rising incidence rates reported in different regions around the world strongly implicate environmental factors. Furthermore, genetic and environmental factors affecting the rate of disease progression and prognosis are poorly understood. However, the lack of well-defined, prospectively evaluated inception cohorts is a critical barrier to developing prognostic markers and models of disease progression in IBD. Consequently, a prospectively accrued inception cohort of IBD patients is needed. We propose to create a prospective, population-based inception cohort of CD and UC patients in the state of Rhode Island. In addition to defining the incidence rates and contemporary natural history of IBD in the US, we intend to collect a variety of biological specimens close to the time of diagnosis. We believe that analysis of these specimens using cutting edge screening technologies (including gene expression arrays, proteomics, metabolomics, and stool bacteriology by non-classical methods) will yield invaluable insights into environmental and genetic factors affecting disease susceptibility and prognosis. The ultimate goal in creating this inception cohort is to facilitate the development of prognostic markers in CD and UC. We intend to identify newly diagnosed cases of Crohn's disease, ulcerative colitis and indeterminate colitis, which are chronic intestinal conditions, in the state of Rhode Island in order to project how common these diseases occur in the United States as a whole. We will follow these patients over time to determine the progression of their disease and to compare this to markers in the blood as a way of developing a system to predict the individual course of disease. [unreadable] [unreadable] [unreadable]